1. Technical Field
The exemplary and non-limiting embodiments described herein relate generally to ambient-light sensors in mobile devices and, more particularly, to narrow-bandwidth photodetectors for mobile devices.
2. Brief Description of Prior Developments
Ambient-light sensors are included in most mobile devices. Such sensors adjust the luminosity of a display of the mobile device according to the background light in order to facilitate legibility and power management. The core element of an ambient-light sensor is a photodetector device. Currently, most ambient-light sensors use silicon photodiodes as the photodetector device. Since silicon is a poor light absorber, it follows that such sensors occupy a fairly large area or are generally quite bulky due to significant thickness being required to absorb sufficient light.
The specifications of various commercially available photodetector devices pose a number of requirements when they are integrated into a case of a mobile device. For example, space on surfaces of mobile devices is at a premium. On one hand, it is generally desirable to have several features embedded in a handset of a mobile device. On the other hand, it is also desirable to have thinner and lighter mobile devices in which a planar surface is occupied by the largest screen possible. A trade-off is generally made with regard to the number of features and the size of the screen, thereby leaving little room for sensors that need a direct interface with the environment.